315/70r17 + stock gears + OTT tune

Regarding the 3rd Gen Tacoma Double Cab Long Bed configuration, equipped with a 3-inch lift, skid plate, rock sliders, and a tonneau cover, I can offer the following insights based on my experience with 315/70r17 tires, stock gear, and with OTT tune.

Initially, concerns regarding the need for regearing were present; however, the current setup provides sufficient power for optimal tire performance. Transitioning from 285/70r17 tires, where an average of 18.2 mpg was observed, the Ultraguage calibration for the 35s surprisingly indicates an average of 19 mpg.

This data reflects driving conditions that include both hilly highway routes and city driving.

I am interested in understanding your experiences with a similar setup.

Could you provide potential explanations for the increased fuel efficiency observed with the 35s compared to the 33s?

Your insights and experiences are highly appreciated.